Method and spinning machine for the production of core yarn

ABSTRACT

A method and device for the production of core yarn ( 63 ), whereby a core yarn ( 12 ) is brought to a fiber slubbing ( 8 ) which has been refined in a drafting system before said slubbing is reinforced by twisting. The core yarn ( 12 ) is embedded in covering fibers. The fiber slubbing is compressed in a compacting device ( 22 ) after the core yarn ( 12 ) has been brought to the slubbing and before twisting occurs.

The invention relates to a method for producing core yarn in which asliver (fiber slubbing) is refined in a drafting frame before it isstabilized by twisting and then fed to a core yarn which is embedded incovering fibers. The invention relates further to a spinning machine forproducing core yarns and having a drafting frame which supplies a fiberslubbing, with a device for feeding the core yarn and a device fortwisting and winding up the core yarn.

The production of core yarn is characterized in that in the formation ofthe yarn and especially upon its drafting to a predetermined finenessand its stabilization by twisting, a core thread is laid into the fiberslubbing and has cover fibers spun around it so that the core thread inthe best case is no longer visible. The core thread determines therebysubstantially the strength and elongation of the generated yarn whilecover fibers above all determine the hand and visual appearance of theyarn. The core threads as a rule are endless synthetic threads while thecover fibers are usually natural staple fibers like cotton and wool.

In a core yarn it is intended that the core thread be embedded ascompletely as possible in the cover fiber which determines the externalappearance. In normal core yarn spinning, this is achieved in that thecore thread is fed into the fiber slubbing as a rule in the last andthus the main drafting field while the cover fibers are laid around thecore thread by the twisting of the fiber band between the output rollerpair [of the drafting frame] and the element from which the twistarises, as a rule a ring spinning spindle. This embedding is effectedrather incompletely at numerous locations along the yarn which resultsin a reduction in quality of the generated core yarn.

It is the object of the invention to improve this embedding of the corethread in the cover fiber. This is achieved by features given in thecorresponding clause of the main claim. With these features, theembedding of the core yarn in the cover fibers is supported by acompaction in addition to a twisting so that, in effect, there are fewergaps and over the length of the yarn a more uniform covering of the corethread by the cover fibers.

The arrangement can be so made that the fiber slubbing supplied by thedrafting frame or in the case of a plurality of fiber slubbings suppliedby the drafting frame at least one of these fiber slubbings before theoutput from the main drafting field or at the input to the compactionzone is met by a core thread, the core thread and fiber slubbing beingcompacted together, and finally subjected to twisting to form the coreyarn. A plurality, especially two fiber slubbings are supplied by thedrafting frame in the case of production of false twist.

An apparatus for carrying out this process has at the output of adrafting frame a compaction device maintained under suction which isformed with a perforation row, i.e. a row running in the direction ofmovement of the fiber slubbing of small suction orifices toward whichthe fibers of the fiber slubbing are sucked. Compaction devices in theform of rotating cylindrical rollers having a perforation row (DE 44 28269 A1) or in the form of an endless flexible belt provided with aperforation row (EP 0 635 590 A2) are known.

An especially effective embedding of the core thread can be achievedwhen, according to the invention, the compaction zone is located asclose as possible to the center of the fiber slubbing which is stillwide upon its approach to the compaction zone. This is especially thecase when the core thread is fed to the inlet side of the output rollerpair of the drafting frame.

In a variation of this embodiment, the core thread can also be feddirectly to the compaction zone. In the case of a suction beltcompaction device, the core thread can be fed from above or from belowto the drafting frame, from the same side as that along which thesuction belt is disposed and can be guided around the deflection end ofthe belt at its upstream side. In other cases, the suction belt has aguide roller arranged at its upstream or inlet side around which thecore thread is guided. When the compaction device has a suction roller,the core thread also can be fed to the periphery of this suction roller.

The compaction of fiber slubbing supplied by a drafting frame affordsthe advantage that the fiber slubbing is gathered tightly upon entry tothe twisting zone upon which it is stabilized to a yarn. In this tightlygathered fiber slubbing, the twisting imparted to the yarn jumpspractically to the clamping line at which the fiber slubbing with thecore yarn emerges, i.e. the spinning triangle is very small. Aconsequence is that the losses of edge fibers which break away areminimal and that the yarn which is produced has few projecting fibers,i.e. reduced hairiness and as a consequence more effective coverage ofthe core thread by the fibers lying tightly thereagainst.

It has been found that this advantageous effect of compaction spinningcan be further increased by carrying out the spinning in athread-balloonless manner or with a reduced thread balloon.Thread-balloonless spinning or spinning with a reduced thread balloon,reduces the tension forces on the yarn in the yarn segment between theapex of the spindle and the output roller pair of the drafting frame andincreases the twist density in this yarn segment. This effect appears toenhance the effect of compaction of the fiber slubbing.

The balloonless spinning or reduced thread balloon spinning can beachieved especially by providing an attachment on the spinning spindleof the ring spinning apparatus in the form of a spinning finger or aspinning crown. The twisting and winding up of the fiber slubbing bymeans of pot spinning apparatus also is effected without balloonformation and reduces the yarn tension forces in the yarn segmentbetween the output roller pair of the drafting frame and the point atwhich the yarn meets the spinning pot. This system also has theadvantages previously described of balloonless spinning.

The Figures of the drawing show embodiments of the invention. Theillustration is largely schematic and not to scale.

It shows

FIG. 1 a first embodiment of the invention in section through thedrafting frame region and through the spindle rows;

FIG. 2 a second embodiment of the drafting device illustrated in FIG. 1,partly in section;

FIG. 3 an elevation of the drafting device of FIG. 1 partly cut away;

FIGS. 4 to 7 further embodiments of the invention in illustrations as inFIG. 1;

FIG. 8 an embodiment for production of false twist as seen in frontelevation.

The spinning machine of the invention comprises a drafting frame 1 ofconventional construction with an input roller pair 2, an intermediateroller pair and an output roller pair 4. The lower rollers 2′, 3′ and 4′of these roller pairs are configured as steel rollers which extend overthe length of the drafting frame region of the spinning machine and havemilling in the vicinities of the work stations.

The upper rollers 2″, 3″ and 4″ are configured as twin rollers which areprovided with elastic jackets 5 and are journaled on a support andloading arm 6 indicated in FIGS. 3 and 8 by means of articulations notshown, and are spring-loaded. The rollers 2′ and 2″ [sic] of theintermediate roller pair 2 [sic] are equipped with belts 7 which areguided also in the support and loading arm 6 or on the stand of thedrafting frame 1 in journaled belt cages. The drafting frame 1 suppliesa strip-like not yet compacted fiber slubbing which has been stretchedto the final fineness and has been indicated at 8. It will beself-understood that the invention is also effective in combination withdrafting frames of other types.

The drafting frame 1 is, according to the invention, juxtaposed with acore thread supply mechanism 9 which in the embodiments of FIGS. 1-3 and5-8 has supply reel rollers 10 which also extend over the length of thedrafting frame region of the spinning machine. On the supply reelrollers 10 rest a core thread spool 11 from which the core thread 12 isfed as illustrated in the drawing in a double-dot dash line [sic] to theinput side of the output roller pair 4. The reel rollers 10 are drivenvia the spinning machine drive in a manner not shown here in greaterdetail with the peripheral speed of the supply roller pair 4. In thismanner it is ensured that the core thread 12 which is fed to the fiberslubbing 8 will have a safety corresponding to the discharge speed ofthe fiber slubbing from the main drafting field between the roller pairs3 and 4.

The core thread supply mechanism 9 is provided with a core thread threadguide 13 which neutralizes the back and forth (traversing) movement ofthe core thread along the core thread spool 11. Since the capacity ofthe compaction device to be described hereinafter to laterally draw thefiber slubbing 8 or its fibers together, the fiber slubbing is providedwith a conventional roving inlet funnel 14 to center it on the draftingframe 1 to prevent the traversing or permitting it to fluctuate onlyslightly in its outer dimensions. So that the core thread 12 is alwaysfed centrally to the fiber slubbing 8, the core thread thread guide 13must be centered to the roving inlet funnel 14 of the drafting frame 1and this position must be maintained even upon fluctuation of the fiberslubbing. This can be ensured by mechanically coupling the roving inletfunnel and the core thread thread guide 13 which has been indicated by aeffective dot-dash line 15 in FIG. 4.

It is, however, also possible to utilize a core thread thread guidewhich is free shiftably laterally and with which the fiber slubbingrunning through the drafting frame is entrained, to center the corethread 12 to the fiber slubbing or follows a slubbing in its back andforth (traversing) movement.

The suction rotor of FIG. 7 can also compact side fiber slubbings 8which are moving back and forth (traversing) widely so that with itsuse, both the fiber slubbing by means of the common roving inlet funnel14 at the inlet of the drafting frame 1 and also the core thread 12 bymeans of the core thread thread guide 13, synchronized with the rovinginlet funnel 14, can move back and forth (traverse) over a wide range.

As has been shown in FIG. 4, the core thread 12 can also be drawn offfrom a stationary core thread cop 16 from above. The core thread cop 16for this purpose is fitted over a holding tube 37 and the core threadpasses through this holding tube. Since, in the embodiment of this FIG.4, the function of the output roller pair of the drafting frame 1 isreplaced by the suction roller 18 to be described in greater detaillater, in combination with the upper roller 37 juxtaposed therewith, thecore thread 12 in this case is fed to this upper roller and is drawnfrom the core thread cop by the said effect of this roller combination.

As shown in FIG. 6, instead of the core thread guide 13, a core threadguide roller 20 with a central thread guide groove 21 is provided. Thiscore thread guide roller 20 can be journalled in the support and loadingarm 6 of the drafting frame. Since it does not move back and forth(traverse), with its use a back and forth (traversing) movement of thefiber slubbing 8 is not possible.

The drafting frame 1 is followed by a compaction device 22 for the fiberslubbing 8 supplied by the drafting frame 1. For the compaction device,an entire range of advantageous embodiments is possible and from whichseveral are illustrated in the Figure of the drawing and are describedhereafter.

In the embodiment of FIGS. 1 through 3, the compaction device has asuction roller 18 which is formed with a perforation 23 in the form ofsmall suction orifices 24 arranged in a line. The suction rollers 18 areconfigured as twin upper rollers and are pressed against two lowerrollers 25 and 26 by the support and loading arm 6 indicated in FIG. 3.The lower roller 25 which is located upstream with respect to the traveldirection of the fiber slubbing 8 is looped by a transport belt 27 whichhas the purpose of guiding the fiber slubbing 8 between the outputroller pair 4 and the suction roller 18.

FIG. 3 also shows the configuration of this suction roller 18. It isconfigured of cup shape and is journalled with its twin roller on anaxle 19 held in the support and loading arm 6. A stationary suctionchamber 28 extends through the open side into the interior of thesuction roller 18. The suction chamber 28 is, like in the variantsdescribed below of the compaction device 22, as shown in FIG. 1,connected via a tube or hose line 29 with a suction source 32 comprisinga suction pump 31 and a motor 30. The suction draw of this suctionsource is restricted by the shield 33 of the suction chamber 28 to apart of the perforation of the suction roller 18 corresponding to acompaction zone 34 only in this compaction zone 34 is the suctionchamber 28 open to the perforation 34 so that only there will thesuction be effective through the perforation at the outer side of thesuction roller 18.

The suction roller 18 is comprised as a rule from steel. To avoid ametallic contact between its circumference and under rollers 25 and 26which as a rule are also composed of steel, leading to wear, noise andslip, either the suction roller 18 or the lower rollers 25, 26 areprovided with elastic jackets 5. In the alternative shown in FIGS. 1 and3, the suction roller 18 is provided with the elastic jacket 5 while inthe embodiment of FIG. 2 the support rollers 25 and 26 are provided withelastic jackets. FIG. 4 shows an embodiment in which a suction rollersimilar to that previously described is used in the form of a suctionlower roller 35. It is configured as a tube provided with theperforation 23 which is journalled in the stand of the drafting frame 1and is driven.

In its interior, the suction chamber 28 is arranged, this suctionchamber having its suction effect limited by a shield 33 to a compactionzone 34. Suction lower roller 35 has at least one upper roller 36juxtaposed therewith and forming a twist stop for a twist generatingdevice, here in the form of a ring spinning device. At the beginning ofthe compaction zone 34, a further upper roller 37 can be arranged. Thisupper roller 37 forms, in this embodiment of the drafting frame 1, incombination with the suction (lower) roller 35, the output roller pairof the main drafting vehicle of the drafting frame. The drafting frame1, in this case has one roller pair fewer than the other embodiments.The upper rollers 36 and 37 have elastic jackets 5 and are journalledand loaded in the support and loading arm 6.

In the embodiment of FIG. 5, the compaction device 22 has a suction belt38 which is composed of elastic synthetic resin and is looped around anupper roller 39. This suction belt 38 has midway of its periphery theperforation 23 in the form of small suction orifices arrayed in a row.In this embodiment as well, the fixed suction chamber 28 is bounded bythe shield 23 which defines the suction chamber within the interior ofthe suction belt 39. It limits the suction effect to the compaction zone34 in which the suction chamber opens along the inner periphery of thesuction belt 38.

The upper rollers 39 rest with their belts 38 on a driven lower roller40 which, like the lower rollers of the drafting frame, extending overthe length of the stretch field region of the spinning machine and drivethe upper rollers and the suction belts. In the embodiment of FIG. 6,the roller below the path of the fiber slubbing 8 and thus thestretching field plane, looped by a suction belt 41 equivalent to thatdescribed, is formed as an under roller 42. It rests upon a drive underroller 43 which is configured as a continuous steel roller extendingover the stretch field region of the spinning machine and serves todrive the belt roller 42 and an upper roller 44 juxtaposed therewith andlying above the stretch field plane.

Within this suction belt 42, also as has been previously described, asuction chamber 28 connected to the suction source 32 is arranged.

Both the suction belt lower roller 42 and the upper roller 44 are formedas twin rollers and are held on and loaded by the support and loadingarm 6 of the drafting frame 1. The pressure upper roller 44 can have anelastic jacket or, since it rests upon the suction belt 41 of elasticsynthetic resin material, can have a steel circumference. The use of aseparate belt twin under roller has the advantage that the suction belts41 can be more easily replaced upon wear.

The compaction device, can, according to FIG. 7 also have a disk shapedsuction rotor 45 which has the perforation 23 along its periphery andwhich is so arranged that the perforated-containing plane lies generallyin the plane tangential to the output roller pair 4 at the draftingframe at its nip. The suction chamber 28 defining the compaction zone isprovided within the interior of the suction rotor 45. The compactionzone 34 extends from the output roller pair 4 by the example, a quarterof the periphery of the suction rotor and at its end, a pressing roller46 is spring biased against the suction rotor 45. The suction rotor 45is, for example, driven by means of an endless circulating an tangentialdrive belt 29 acting via a pressing roller 48 against the shaft 47connected thereto. The suction rotor 45 is driven with a speed whichcorresponds to the supply speed of the fiber slubbing produced by theoutput roller pair 4. The lower rollers 2′, 3′, 4′ of the drafting frame1 and the lower rollers 25, 26, 35, 40 and 43 of the various variants ofthe compaction device 22 are, as represented by the dot dash line 50 inFIG. 1, driven by means of a drive not shown or by means of individualdrives on speed ratios which are staggered from one to another.

In the embodiments of FIGS. 1, 2, 3, 5, 6 and 8, the lower rollers 25,26, 40 or 42 from which the fiber slubbing 8 is delivered and from whichthe twist is generated, have a diameter which is selected asadvantageous for the process of the respective staple fiber. Thisdiameter amounts for example in the case of cotton to 29 mm to 33 mm.The compaction device 22 is followed in the embodiments of FIGS. 1, 4and 5 as well as 7 and 8 by a conventional ring spinning device 51 witha spindle rail 52, spinning spindles 53, ring rail 54, spinning ring 55,travellers 56 and thread guide 57. FIG. 6 shows an embodiment in whichthe compaction device 22 is followed by a conventional pot spinningdevice 58 with a pot rail 59 in which a spinning pot 60 is journalledand in the middle of which and around an upwardly and downwardly movingthread guide tube 61, a spun cake 62 is formed.

In operation, the drafting frame 1 supplies a fiber slubbing 8 from theoutput roller pair 4 which, as a consequence of the diameter of theincoming roving and the drafting processing has a certain width intowhich the core thread 12 is centrally laid in. By the suction draw ofone of the aforedescribed compaction devices 22, the fibers of the fiberslubbing 8 are drawn laterally to a narrow line along the suctionopenings 24 of the respective compaction device, thereby compacting thefiber slubbing 8 and causing the fibers to densely hug the core thread12. In this compacted state, the fiber slubbing 8 and the core thread 12encased therein are fed from the nip defined by the compaction device tothe ring spinning device 51 or the pot spinning device 58 from which atwist is produced to stabilize a core yarn 63 and enable that core yarnto be wound up. FIG. 4 shows the use of a ring spinning device 51without a thread balloon or with a reduced thread balloon. At the apexof the spinning spindle 53 for this purpose a so-called spinning finger64 is disposed which, in coaction with the thread guide 57 captures theoncoming core yarn and loops it around the yarn sleeve 65 and guides itwithout a thread balloon or with a very small reduced thread balloon tothe traveller 56. Instead of the spinning finger 64, an equivalentlyoperating spinning crown can be used as is known and thus not furtherdescribed here or illustrated.

Finally, in FIG. 8, the possibility has been illustrated of a compactiondevice 22, for example, that of FIG. 5, for the production of falsetwists. For this purpose, the suction belt 38 has a perforation 23 inthe form of two mutually spaced rows of suction orifices 24 by means ofwhich fiber slubbings 8, 8′ are separately compacted as supplied fromrespective working stations from two roving bobbins 67 and are describedin drafting frame 1. After the compacted fiber slubbings pass from thelower roller 40 of the compaction device 22, the two fiber slubbings runtogether at the uniting point 68 and are twisted to a false twist 66 bya ring spinning device 51 or by a pot spinning device 58 the false twistbeing wound up.

In producing the false twist 66, two fiber slubbings 8, 8′ are joined.As a rule, it is sufficient for productions of core yarn false twist tofeed a core thread to only one of the fiber slubbings 8. In FIG. 8 onlyone core thread thread spool 11 is shown whose core thread 12 is fed tothe right hand fiber slubbing 8.

It will be self understood that the described and illustrated variantsof the components of the spinning machine of the invention, for examplethe drafting frame 1, the compaction device 22, the twisting and wind updevice 50 or 58 and the optional devices for balloonless spinning bymeans of spinning finger 64 and the device for production of the falsetwist can be used in other combinations than those illustrated anddescribed effectively.

REFERENCE NUMERAL LIST

1 Drafting Frame

2 Input roll pair

3 Intermediate roll pair

4 Output roll pair

2′, 3′, 4′ Lower rollers

2″, 3″, 4″ Upper rollers

5 Elastic jacket

6 Support and Loading Arm

7 Belts

8, 8″ Fiber Slubbing

9 Core Thread Supply Mechanism

10 Delivery Roll

11 Core Thread Spool

12 Core Thread

13 Core Thread Thread Guide

14 Roving Feed Funnel

15 Effective Line

16 Core Thread Cop

17 Holder Tube

18 Suction Roller (FIGS. 1 through 3)

19 Upper Roller

20 Core Thread Guide Roller

21 Thread Guide Groove

22 Compaction Device

23 Perforation

24 Suction Orifices

25, 26 Lower Roller

27 Transport Belt

28 Suction Chamber

29 Tube or Hose Line

30 Motor

31 Suction Pump

32 Suction Source

33 Shield

34 Compaction Zone

35 Suction Roller (FIG. 4)

36, 37 Upper Rollers

38 Suction Belts (FIG. 5)

39 Upper Rollers

40 Lower Rollers

41 Suction Belt (FIG. 6)

42 Lower Rollers

43 Drive lower rollers

44 Upper Rollers

45 Suction Rotor

46 Pressing Roller

47 Shaft

48 Pressing Roller

49 Tangential Drive Belt

50 Effective Line

51 Ring Spinning Device

52 Spindle Rail

53 Spinning Spindle

54 Ring Rail

55 Spinning Ring

56 Traveller

57 Thread Guide

58 Pot Spinning Device

59 Pot Rail

60 Spinning Pot

61 Thread Guide Tube

62 Spinning Core

63 Core Yarn

64 Spinning Finger

65 Yarn Sleeve

66 False Twist

67 Roving Bobbin

68 Joining Point

What is claimed is:
 1. A spinning machine for producing a core yarn,comprising: a drafting frame having a plurality of roller pairstraversed in succession by a fiber slubbing and subjecting said fiberslubbing to drafting during passage through said drafting frame, saiddrafting frame having at an output thereof a compaction device, saidcompaction device comprising a driven endless surface formed with aperforation extending around a periphery of said compaction device, asuction source connected to said perforation to apply suctiontherethrough to said slubbing, thereby drawing fibers of said slubbingtogether, and at least one roller juxtaposed with said surface wherebysaid slubbing passes between said roller and said surface; a core threadsupply for feeding a core thread into said slubbing centrally of saidperforation and directly on said surface whereby said core thread isenveloped in said slubbing; and a spinning frame downstream of saiddrafting frame and receiving the slubbing with the core thread envelopedtherein for spinning the slubbing and the core thread enveloped thereininto a core yarn.
 2. The spinning machine defined in claim 1 whereinsaid roller is a guide roller positioned to guide said core thread ontosaid surface.
 3. The spinning machine defined in claim 1 wherein saidperforation is a row of orifices formed in said surface and said sectionsource includes an element within said compaction device restricting theapplication of suction to a limited number of said orifices in acompaction zone.
 4. The spinning machine defined in claim 3 wherein saidsurface is formed by a belt.
 5. The spinning machine defined in claim 3wherein said surface is formed by a roller.
 6. The spinning machine asdefined in claim 3 wherein said roller is provided above said surface.7. The spinning machine as defined in claim 3 wherein said roller isprovided below said surface.
 8. The spinning machine as defined in claim3 wherein said perforation comprises two rows of orifices.
 9. Thespinning machine as defined in claim 3 wherein said spinning frame is aring spinning frame.
 10. The spinning machine as defined in claim 3wherein said spinning frame is a pot spinning frame.